Fuse



Patented Aug. 30, 1932 UNITED STATES JAY R. FOGAL, F SAN FRANCISCO, CALIFORNIA FUSE Application filed May 27, 1931.

This invention relates to fuses and has particular reference to fuses of the Ventilating type embodying means to readily permit visual inspection of the fuse link.

\ 6 The primary object of the present invention is to provide a fuse wherein the fusible element may be readily observed to facilitate inspection.

Another object is to provide a fuse of this character which shall present a smooth eX- terior that is devoid of all projections and which is similar in general appearance to the ordinary fuse.

A further object is to provide a fuse. of the aforesaid character wherein a sleeve is normally maintained in closed position with respect to an observation aperture and is automatically returned to such position after the sleeve has been moved to observe the fusible element through such aperture.

A still further object is to provide a fuse of this character which shall be simple in construction, inexpensive to manufacture and which may be easily operated to permit inr spection of the fusible element. t

With the foregoing and other objects 1n view, the invention may be stated to consist in the various novel features of construction and arrangement or combination, all of which will be full described hereinafter and pointed out in the appended claims.

In the drawing accompanying and forming part of this application;

Fig. 1 is a side elevation with parts broken away of a fuse constructed in accordance with my invention;

Fig. 2 is a longitudinal sectional view taken on the line 2-2 of Fig. 1, and showing the parts in normal position; a-nd Fig. 3 is a similar view but showing the outer sleeve moved to align the observation apertures.

Describing the various parts by reference characters, 1 denotes the body portion of the fuse which is made of insulating material and which is preferably cylindrical in shape and provided with diametrically opposed apertures 2. Projecting from each end of the body portion is an internally and eX- ternally threaded sleeve 3. A sheet metal Serial No. 540,478.

cup shaped member 4 is engaged with the internal threads to define a spiral vent passage 5 which communicates at one end with the interior of the fuse and at the other end with a plurality of apertures 6 formed in an end cap 7. These end caps are threaded on the projecting ends of the sleeves 3 and each end cap is formed with an annular groove 8 which receives a longitudinally slidable sleeve 9.

Interposed between each end cap 7 and cup shaped member 4 is a lock washer 10 of any suitablev type which closely embraces a knife blade contact 11 that projects through the end cap. A fusible element 12 interconnects the imier ends of the knife blade contacts and extends through the longitudinal axis of the fuse housing.

The sleeve 9 is slidably mounted on the cylindrical housing 1, and a spring 14 interposed between an end cap 7 and the end of the sleeve serves normally to maintain said sleeve engaged with the opposite end cap. In Fig. 2, I have shown the spring 14 positioned in annular groove 8 in the right hand end cap 7 and the sleeve forced toward the left hand end cap. The sleeve is formed with a pair of diametrically opposed obvservation apertures 15 which are adapted to align with apertures 2 in the housingvwhen the sleeve 9 is moved to the right, as shown in Fig. 3, thereby permitting the fusible element 12 to be readily observed. When the sleeve is released, and moves to the left, as shown in Fig. 2, plates 16, which are positioned'inside the housing and fastened to the sleeve by pins 17, normally cover the apertures 2. These plates and the sleeve 9 provide a double seal for the apertures 2. A pair of pins 18 which project from housing 1 and engage in longitudinal slots 19 in the l sleeve prevent rotation of the sleeve with respect to the housing and maintain the apertures 15 and 2 in longitudinal alignment.

When the fusible element 12 melts, due to a short circuit or other overload, the gases generated will escape through vent passages 5 and ports 6 to the atmosphere, thereby avoiding rupture of the housing 1. If at any time it is desired to inspect the fusible element, it may be easily observed by sliding sleeve 9 longitudinally on the housing to Within said housing and having end con.

tacts, and a sleeve slidable longitudinally on said sleeve and housing having apertures adapted to align to permit observation of said fusible element, and means for normally moving and holding said sleeve With said apertures out of alignment.

In testimony whereof I aflix my signature. JAY R. FOGAL.

said housing, said sleeve and housing hav- 1 i ing apertures adapted to align to permit observation rofrsaid fusible element.

2. A fuse of the Character set 4forth comprising a housing, a fusible'element disposed Within'said housing and having end'contacts, ga'sleeve slidable longitudinally `on said v"housin'g,'said sleeveand housing having apertures adapted to align Lto IpermitV observation 'of said vfusible element, vand resilient means arranged to `normally -m'ove 'and hold 'the sleeve With said apertures out of alignment.

3. A fuseof the'character-'set forth vCornprising a housing having -a fusible element therein,fanend cap disposed at each end -o'f said' housing, 4saidend caps each having an annular recess, and ya sleeve slidable ylong ai- Studi'nally offsaidfhousing and engaged in said annular recesses, said sleeve and housing having apertures adapted to align -to permit observation'of Asaid lfusible element.

. 4a. A fuse-of theeha'raeter set Vforth Comprising a housing having a fusible `element Etherein, an end cap 4disposedatl eaeh'end of "said ihousing, said en'd'oaps each having an annular recess, a sleeve 'srlidab'le longitudinallyofsaid Ahousing and -engaged in said annular "recesses, Asaid sleeve i' and housing having YVapertures"adapted to :align to permit ob- Aservationof said fusible'element, and aresilient element disposed in one Yof said lr'eeesses'a'n'd adapted to normally move and hold isaid 'sleeve with said apertures out of alignment.

"5. A Y:fuse ofthe charaet'erset forth com-= prisi'ng `a 'housing having a :fusible element "therein, ajthreaded Vsleeve projecting from leach endfof said housing, an'end cap engaged With the thread of eah sleeve, saidend caps each having an annular recess, va sleeveslidable longitudinally of said housing and hav- "ingt'he ends thereof engaged in said annular ;r.'ecesse`s,said sleeve and housing having apertures adapted to align to permit observation of :said fusi-ble element, land means for normally l'moving and holding said sleeve With lsaid apertures-out of alignment.

6. A vr'fuse 'ofthe character set forth -oomp'rising a housing having a fusible'element therein, a sleeve s'lidable 'longitudinally on said housing, means for preventing 'rotation 'of said sleeve With respect 'to said housing, 

